This invention relates to a proximity switch which can be operated without physical contact. The switch has an elongated columnar housing with a cross section having orthogonal axes of symmetry which are perpendicular to its principal axis. The housing is divided into at least two housing parts joined at abutting surfaces which lie at an angle to the principal axis.
In a proximity switch of the above-mentioned general type known from British Pat. No. 1,566,089, the housing parts are bounded by surfaces which face each other and which extend at a sharp angle, preferably 45.degree., to the longitudinal axis of the housing. In a proximity switch of this kind it is possible to align the operating axis of the sensing head with the longitudinal axis of the prismatic housing as well as transversely thereto. However, when the sensing head is arranged with its operating axis transverse to the longitudinal axis of the housing, the sensor surface extends beyond the lateral outside surface of the housing. This is necessary so that the cup core of the sensor, which has a predetermined height, can be accommodated in the cross section of the columnar housing. This is particularly true when the housing has a circular cross section.